Licensed Electrical Contractor Grounding and Bonding Questions and Answers

Question 1

A service is supplied by three parallel 500 kcmil copper conductors per phase. What is the minimum size copper supply-side bonding jumper required for this installation?

Accepted Answer

3/0 AWG

Answer

2/0 AWG

Answer

1/0 AWG

Answer

250 kcmil

Question 2

When grounding a separately derived system, such as a transformer, what is the primary location for connecting the grounding electrode conductor?

Accepted Answer

At the same point on the system where the system bonding jumper is connected.

Answer

To the closest available grounding electrode.

Answer

Directly to the building's structural steel, bypassing all other connections.

Answer

At the first disconnecting means on the secondary side.

Question 3

An electrical service is supplied with 4/0 AWG copper ungrounded conductors. The grounding electrode is a ground rod. What is the minimum size copper grounding electrode conductor (GEC) required?

Accepted Answer

6 AWG

Answer

4 AWG

Answer

8 AWG

Answer

2 AWG

Question 4

Which of the following must be bonded to the electrical service for a building with an interior metal water piping system?

Accepted Answer

The metal water piping system.

Answer

Only the cold water piping.

Answer

Only isolated sections of metal pipe longer than 10 feet.

Answer

Only the hot water piping.

Question 5

A main bonding jumper is used to connect which two components at the service equipment?

Accepted Answer

The equipment grounding conductor bus and the grounded (neutral) conductor bus.

Answer

The grounding electrode and the service enclosure.

Answer

The grounded (neutral) conductor and the grounding electrode conductor.

Answer

The ungrounded conductors and the service enclosure.

Question 6

In a building with multiple separately derived systems, what does the NEC permit regarding the grounding electrode conductor?

Accepted Answer

A common grounding electrode conductor can be used, with taps run from each individual system.

Answer

Each system must have its own separate grounding electrode conductor run to an isolated grounding electrode.

Answer

Only the largest separately derived system is required to be connected to the grounding electrode system.

Answer

The systems can be grounded to each other in series, with the last one connected to the grounding electrode.